If I may make a suggestion. When MRE's are left in heat(such as a hot vehicle) their shelf life is rapidly reduced. Additionally, I've never had one but I hear they taste terrible and will cause horrible constipation. Also, MRE's are expensive.
You should consider ordering some freeze dried food. MRE's last 5-7 years if stored properly while freeze dried food lasts 10 for the pouches or 30 years for the cans. The freeze dried pouches will be lighter than the MRE's and probably much tastier. The only advantage the MRE has is that you don't need hot water to eat it.
Here is what I've been buying lately.
http://www.thereadystore.com/food-storage/brand/mountain-house/mountain-house-just-in-case-essential-assortment-bucket
http://www.thereadystore.com/food-storage/supply-size/pouches?p=3
I don't work for The Ready Store, I'm just a very happy customer. If you sign up for their emails you become a VIP customer which earns you points which equals $$. Also, they will notify you of special sales via email. The run sales often but for the VIP customers you can call at any time and they will take additional dollars off your order just because you called.
If you decide to order, here is a coupon code for $10 off. If you spend $100 you get free shipping. I would recommend you call Marc and see what kind of deal you can get over the phone.
Marc Silva 800-773-5331x107
Coupon code-- 10C132